Problem: Simplify the following expression: $n = \dfrac{-4}{5t} - \dfrac{-9}{5t}$
Since the expressions have the same denominator we simply combine the numerators: $n = \dfrac{-4 - (-9)}{5t}$ Combine like terms: $n = \dfrac{5}{5t}$ Simplify by dividing numerator and denominator by 5: $n = \dfrac{1}{t}$